A study raises new questions about the safety of voice-activated technology in many new cars.

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When driving, don’t talk to your car — or your phone.

That’s the underlying message of new neuroscience published Thursday that raises new questions about the safety of voice-activated technology in many new cars. The technology, heralded by many automakers, allows consumers to interact with their phones and their cars by issuing voice commands, rather than pushing buttons on the dashboard or phone.

But the research (and an accompanying video) shows that the technology can be a powerful distraction, and a lingering one. The research found that the most complicated voice-activated systems can take a motorist’s mind off the road for as long as 27 seconds after he or she stops interacting with the system.

Even less complex systems can leave the driver distracted for 15 seconds after a motorist disengages, the research shows.

These problems occur too with voice-activated systems from Apple, Google and Microsoft, according to the study.

This lingering distraction reflects the time required for drivers to reorient themselves to the road after interacting with their cars’ voice-activated technology, according to the study’s lead scientist, David Strayer, a neuroscientist at the University of Utah.

He said that using this technology required the same kind of brain power as “balancing a checkbook while driving.”

“When you hang up, you have to figure out where you are, how fast you’re going, where other vehicles are,” he said.

His research was funded by the AAA Foundation for Traffic Safety, a nonprofit research group.

In Strayer’s latest research, he compared the mental energy required by drivers to use more than 10 different voice-activated systems.

The most distracting, he found, belonged to the Mazda 6, followed by Microsoft’s Cortana system, and cars from Hyundai, Chrysler, Nissan and Volkswagen. Apple’s Siri system also created a “high distraction,” the research found. The system in the Chevrolet Equinox and Buick LaCrosse created “moderate distraction,” it found.

Strayer said that when drivers disengage from the systems, the mental workload drops off in tiers, with the heaviest distraction passing after six seconds, then ebbing further after three more seconds, then again a few seconds later.

He said the challenges appeared more severe for drivers over the age of 50.